Trench and excavation cave-ins account for a number of fatalities and serious injuries within the construction industry. For this reason, many serious considerations must be made while trenching or excavating.

What are the major causes of cave-ins?
Answer: Inadequate shoring, improper slopes on banks, poor analysis of soil conditions, defective shoring materials, nearby loads, vibrations and weather conditions.

Several precautions can and must be taken to help eliminate excavation hazards
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The first step is to check for and locate any underground utilities or other buried items. Then, the soil conditions must be carefully evaluated to determine the protective system needed.

Wear your hard hat at all times. Also wear rugged boots to protect your feet.

Excavate trenching banks to their proper slope ratio. Where necessary, straight banks should be shored. Weather conditions can greatly affect sloping and shoring.

Material stock piled nearby can increase the pressure on trench or excavation walls. Keep heavy equipment and materials such as pipe and timbers well away from the excavation site. Maintain a minimum of two feet between any materials, including the spoils pile and the edge of the trench.

Vibrations from equipment passing by can contribute to cave-ins by loosening the soil. Any soil vibration can endanger a shoring system. Compaction operations cause vibration; therefore, check soil conditions before, during and after compaction. A Competent person is to inspect shoring systems daily.

Since quick exits are a must, ladder are to be located no more that 25 feet away from any worker. Ladders must extend from the floor of the excavation to 3 feet above the top and must be secured at the top.

References:

1926.651 Specific Excavation Requirements

1926.652 Requirements for protective systems

APPENDIX A TO SUBPART P - SOIL CLASSIFICATION

APPENDIX B TO SUBPART P - SLOPING AND BENCHING

APPENDIX C TO SUBPART P - TIMBER SHORING FOR TRENCHES

APPENDIX D TO SUBPART P - ALUMINUM HYDRAULIC SHORING FOR TRENCHES

APPENDIX E TO SUBPART P - ALTERNATIVES TO TIMBER SHORING

APPENDIX F TO SUBPART P - SELECTION OF PROTECTIVE SYSTEMS